South Africa fast bowler Morne Morkel and all-rounder JP Duminy will undergo late fitness tests ahead of Saturday's (Sunday NZ time) triangular series final against Australia in Harare.

South Africa, who have already lost all-rounder Ryan McLaren to injury in the series, will give the players until just before the start of play to prove their fitness.

"MRI Scans were done on Morne's right shoulder and JP's left knee earlier this week. Morne's scan confirmed an aggravation of a pre-existing rotator cuff tear which has worsened due to a high workload in Zimbabwe, while JP's scan confirmed a patella tendinopathy diagnosis," Proteas team manager Mohammed Moosajee said in a statement.

"Both players have been managed through the last few games by physiotherapist Brandon Jackson but due to the worsening nature of their injuries recently, their availability for tomorrow's final will be subject to a late fitness test in the morning."

The side may feel the loss of Duminy more as he performs not just as a top six batsman, but also provides a spin option on the Harare Sports Club wickets that have turned prodigiously in recent matches.